Precoding indication for simultaneous multi-panel ul transmission

Abstract

Methods and apparatuses for precoding indication for simultaneous multi-panel UL transmission are disclosed. In one embodiment, a UE comprises a transceiver; and a processor coupled to the transceiver, wherein the processor is configured to receive, via the transceiver, a DCI containing at least one TPMI field indicating a precoding matrix, the DCI schedules a multi-panel simultaneous PUSCH transmission with up to 4 layers; and determine, for the UE equipped with a first panel and a second panel, a precoding matrix used for the first panel and a precoding matrix used for the second panel according to the at least one TPMI field.

1 . A user equipment (UE) for wireless communication, comprising:
 at least one memory; and   at least one processor coupled with the at least one memory and configured to cause the UE to:   receive downlink control information (DCI) containing a first transmit precoding matrix indicator (TPMI) field and a second TPMI field that schedules a spatial division multiplex (SDM)-based multi-panel simultaneous physical uplink shared channel (PUSCH) transmission with up to four layers; and   determine, for the UE equipped with a first panel and a second panel, a first precoding matrix indicated by the first TPMI field is the precoding matrix used for the first panel and a second precoding matrix indicated by the second TPMI field is the precoding matrix used for the second panel.   
     
     
         2 . (canceled) 
     
     
         3 . The UE of  claim 1 , wherein the first precoding matrix indicated by the first TPMI field and the second precoding matrix indicated by the second TPMI field are the precoding matrix used for the first panel and the second panel. 
     
     
         4 . The UE of  claim 1 , wherein a rank of the first precoding matrix indicated by the first TPMI field is equal to the rank of the second precoding matrix indicated by the second TPMI field. 
     
     
         5 . The UE of  claim 1 , wherein:
 the DCI contains a transmit rank indicator (TRI) field; and   the first precoding matrix used for the first panel and the second precoding matrix used for the second panel are determined by the precoding matrix indicated by the TPMI field and a rank combination corresponding to the first panel and the second panel indicated by the TRI field.   
     
     
         6 . The UE of  claim 5 , wherein:
 the rank combination includes first rank (rank1) for the first panel and second rank (rank2) for the second panel, wherein a sum of rank1 and rank2 is equal to a rank of the precoding matrix indicated by the TPMI field;   a matrix part of the first precoding matrix used for the first panel is first rank1 part of the matrix part of the first precoding matrix indicated by the TPMI field, a scaling factor of the first precoding matrix used for the first panel is determined by the matrix part of the first precoding matrix used for the first panel configured for power of modulated data does not increase after applying the first precoding matrix used for the first panel and transmit power of pre-coded data over each used antenna port of the first panel is the same; and   a matrix part of the second precoding matrix used for the second panel is last rank2 part of the matrix part of the second precoding matrix indicated by the TPMI field, a scaling factor of the second precoding matrix used for the second panel is determined by the matrix part of the second precoding matrix used for the second panel configured for power of modulated data does not increase after applying the second precoding matrix used for the second panel and the transmit power of each used antenna port of the second panel is the same.   
     
     
         7 . The UE of  claim 6 , wherein, when the precoding matrix is used for a panel having four antenna ports, the power of the modulated data does not increase after applying the precoding matrix comprising:
 when all of the four antenna ports are used for data transmission, the power of the modulated data does not change after applying the precoding matrix, and   when one or two or three antenna ports are not used for the data transmission, the scaling factor of the precoding matrix is fixed as one-half.   
     
     
         8 . (canceled) 
     
     
         9 . The UE of  claim 1 , wherein:
 the DCI contains an antenna port(s) field; and   the first precoding matrix used for the first panel and the second precoding matrix used for the second panel are determined by the precoding matrix indicated by the TPMI field and a first rank of the first precoding matrix used for the first panel and a second rank of the second precoding matrix used for the second panel indicated by the antenna port(s) field.   
     
     
         10 . The UE of  claim 9 , wherein:
 a sum of the first rank (rank1) and a second rank (rank2) is equal to a rank of the precoding matrix indicated by the TPMI field;   a matrix part of the first precoding matrix used for the first panel is first rank1 part of the matrix part of the first precoding matrix indicated by the TPMI field, a scaling factor of the first precoding matrix used for the first panel is determined by the matrix part of the first precoding matrix used for the first panel configured for power of modulated data does not increase after applying the first precoding matrix used for the first panel and transmit power of pre-coded data over each used antenna port of the first panel is the same; and   matrix part of the second precoding matrix used for the second panel is last rank2 part of the matrix part of the second precoding matrix indicated by the TPMI field, a scaling factor of the second precoding matrix used for the second panel is determined by the matrix part of the second precoding matrix used for the second panel configured for power of modulated data does not increase after applying the second precoding matrix used for the second panel and the transmit power of the pre-coded data over each used antenna port of the second panel is the same.   
     
     
         11 . The UE of  claim 10 , wherein, when the precoding matrix is used for a panel having four antenna ports, the power of the modulated data does not increase after applying the precoding matrix comprising:
 when all of the four antenna ports are used for data transmission, the power of the modulated data does not change after applying the precoding matrix, and   when one or two or three antenna ports are not used for the data transmission, the scaling factor of the precoding matrix is fixed as one-half.   
     
     
         12 . The UE of  claim 1 , wherein the at least one processor is configured to cause the UE to receive a max rank restriction to indicate a maximal total number of layers of the multi-panel simultaneous PUSCH transmission. 
     
     
         13 . The UE of  claim 12 , wherein a rank of the precoding matrix indicated by the TPMI field is equal to a total number of layers of the multi-panel simultaneous PUSCH transmission, wherein the total number is equal to or smaller than the maximal total number. 
     
     
         14 . A method performed by a user equipment (UE), the method comprising:
 receiving downlink control information (DCI) containing a first transmit precoding matrix indicator (TPMI) field and a second TPMI field that schedules a spatial division multiplex (SDM)-based multi-panel simultaneous physical uplink shared channel (PUSCH) transmission with up to four layers; and   determining, for the UE equipped with a first panel and a second panel, a first precoding matrix indicated by the first TPMI field is the precoding matrix used for the first panel and a second precoding matrix indicated by the second TPMI field is the precoding matrix used for the second panel.   
     
     
         15 . A base unit, comprising:
 at least one memory; and   at least one processor coupled with the at least one memory and configured to cause the base unit to:   determine, for a UE equipped with a first panel and a second panel, a first precoding matrix used for a first panel and a second precoding matrix used for a second panel; and   transmit downlink control information (DCI) that schedules a multi-panel simultaneous PUSCH transmission with up to 4 layers, the DCI contains at least one TPMI field indicating the precoding matrix used for the first panel and the precoding matrix used for the second panel.   
     
     
         16 . A processor for wireless communication, comprising:
 at least one controller coupled with at least one memory and configured to cause the processor to:
 receive downlink control information (DCI) containing a first transmit precoding matrix indicator (TPMI) field and a second TPMI field that schedules a spatial division  1  multiplex (SDM)-based multi-panel simultaneous physical uplink shared channel (PUSCH) transmission with up to four layers; and 
 determine, for a user equipment (UE) equipped with a first panel and a second panel, a first precoding matrix indicated by the first TPMI field is the precoding matrix used for the first panel and a second precoding matrix indicated by the second TPMI field is the precoding matrix used for the second panel. 
   
     
     
         17 . The processor of  claim 16 , wherein the first precoding matrix indicated by the first TPMI field and the second precoding matrix indicated by the second TPMI field are the precoding matrix used for the first panel and the second panel. 
     
     
         18 . The processor of  claim 16 , wherein a rank of the first precoding matrix indicated by the first TPMI field is equal to the rank of the second precoding matrix indicated by the second TPMI field. 
     
     
         19 . The processor of  claim 16 , wherein:
 the DCI contains a transmit rank indicator (TRI) field; and   the first precoding matrix used for the first panel and the second precoding matrix used for the second panel are determined by the precoding matrix indicated by the TPMI field and a rank combination corresponding to the first panel and the second panel indicated by the TRI field.   
     
     
         20 . The processor of  claim 19 , wherein:
 the rank combination includes first rank (rank1) for the first panel and second rank (rank2) for the second panel, wherein a sum of rank1 and rank2 is equal to a rank of the precoding matrix indicated by the TPMI field;   a matrix part of the first precoding matrix used for the first panel is first rank1 part of the matrix part of the first precoding matrix indicated by the TPMI field, a scaling factor of the first precoding matrix used for the first panel is determined by the matrix part of the first precoding matrix used for the first panel configured for power of modulated data does not increase after applying the first precoding matrix used for the first panel and transmit power of pre-coded data over each used antenna port of the first panel is the same; and   a matrix part of the second precoding matrix used for the second panel is last rank2 part of the matrix part of the second precoding matrix indicated by the TPMI field, a scaling factor of the second precoding matrix used for the second panel is determined by the matrix part of the second precoding matrix used for the second panel configured for power of modulated data does not increase after applying the second precoding matrix used for the second panel and the transmit power of each used antenna port of the second panel is the same.   
     
     
         21 . The processor of  claim 20 , wherein, when the precoding matrix is used for a panel having four antenna ports, the power of the modulated data does not increase after applying the precoding matrix comprising:
 when all of the four antenna ports are used for data transmission, the power of the modulated data does not change after applying the precoding matrix, and   when one or two or three antenna ports are not used for the data transmission, the scaling factor of the precoding matrix is fixed as one-half.   
     
     
         22 . The processor of  claim 16 , wherein:
 the DCI contains an antenna port(s) field; and   the first precoding matrix used for the first panel and the second precoding matrix used for the second panel are determined by the precoding matrix indicated by the TPMI field and a first rank of the first precoding matrix used for the first panel and a second rank of the second precoding matrix used for the second panel indicated by the antenna port(s) field.